740
FXUS61 KLWX 101956
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
256 PM EST Wed Dec 10 2025

.SYNOPSIS...
Behind exiting high pressure, a quick moving clipper system
will pass through the Great Lakes. A secondary cold front will
follow suit on Thursday morning. Another fast moving frontal
system will likely reach the area by midday Friday. A wave of
low pressure may impact the area Saturday night into Sunday
before Arctic high pressure moves in by early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Abundant clouds in WAA were streaming across the area as of
19Z/2PM EST, though brief breaks were evident around GW Nat`l
Forest/Shenandoah Mountain. Most snow has been limited to above
3500 feet over the Appalachians, though snow levels will quickly
lower to 2500 feet over the next hour if not sooner. Even more
rapid lowering of snow levels is expected by dark as CAA ensues.
Bursts of snow are expected roughly 5-10 PM generally near and
west of US-220 from Cumberland MD to Monterey VA.

Moderate to heavy snow will impact areas along and west of the
Alleghenies throughout much of the evening and night. While
some brief lulls are possible, the blustery winds should lead to
significant travel issues given the expected near whiteout
conditions. Snow totals are likely to be in the 4 to 7 inch
range, with locally 8 to 12 inches across the western-facing
slopes above 2,500 foot elevation along and west of the
Allegheny Front. Travel across this area will be hazardous and
thus not recommended. Check out weather.gov/lwx/winter for more
information on this winter storm.

Outside of the Blizzard Warnings, a pair of Winter Weather
Advisories are in place across western Highland and eastern
Garrett Counties. Storm totals of around 2 to 3 inches are
expected, locally to around 5 inches across the western-facing
slopes above 2,500 foot elevation. Like areas inside the
Blizzard Warnings, blustery wind gusts of around 35 to 45 mph
are possible which will aid in significant (though more
intermittent) reductions in visibility. For the eastern
portions of the Alleghenies, the low Froude numbers should keep
amounts much lower (under an inch, except perhaps in localized
squalls this evening).

Elsewhere, winds shift over to west-northwesterly into the
night with gusts around 15 to 25 mph. Skies clear out east of
the Alleghenies as cold, dry advection ensues. Overnight lows
are forecast to fall into the mid 20s to low 30s, with teens
over the Alleghenies where the blizzard continues.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
The strong shortwave driving this system begins to exit off the
Delmarva Peninsula early Thursday. At the same time, an upper
low tracks southeastward from Ontario toward New England. The
net result of this pattern aloft yields a sub-504 dm mid-level
low centered over upstate New York on Thursday afternoon.
Relative to early/mid-December climatology, these low heights
are around 2 standard deviations below average. The shot of cold
advection picks up on Thursday as 850-mb temperatures fall into
the -12 to -15C range. Thermodynamic profiles are likely to be
dry adiabatic down to the surface which at least raises highs
into the 30s. For those in the mountains, upper teens to 20s
should be commonplace. West-northwesterlies remain gusty which
ushers daytime wind chills into the 20s (single digits down to
around -5F across the Alleghenies). Additionally, this comes
with continued snow showers with Blizzard Warnings in effect
until 10 AM Thursday. While snow tapers off through the day,
blowing snow will likely remain an issue. Additional flurries or
an isolated snow shower or two may linger in modest upslope flow.

Elevated wind fields decrease into Thursday night as a weak area
of high pressure builds in from the Tennessee Valley. Forecast
lows drop into the upper teens to mid 20s, with upper 20s around
the DC and Baltimore urban corridors.

Below average temperatures continue into Friday as highs largely
do not escape the 30s, with 20s in the mountains. As the large
cyclonic circulation aloft shifts focus toward the Canadian
Maritimes, a progressive northwesterly flow aloft sets up over
the north-central to northeastern U.S. An embedded clipper-type
system pushes through the region on Friday. At least several
inches of snow is becoming increasingly likely along and west of
the Allegheny Front, especially south of US-33. There is a
chance of some light snow and rapidly falling temperatures east
of the mountains for the evening commute. If precip arrives
earlier, the morning commute could be impacted, as well, but
certainty is low. Spread in guidance remains large, but trends
in the ECMWF-AIFS have been consistently further south and drier
over the last 2 days. Even so, deep lift through the DGZ could
result in a rather broad area of light snow at times.

Some snow showers linger into Friday night, especially along the
Alleghenies where upslope flow continues. Underneath mostly
cloudy skies, low temperatures will fall into the 20s.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A weak ridge of high pressure will become centered over the region
on Saturday. Mostly cloudy skies and dry conditions are expected,
with highs in the upper 30s to mid 40s for most (20s mountains).
Meanwhile, much further to the west, the waveguide across North
America will start to amplify as a system tracks toward the British
Columbia coast. A ridgebuilding event will ensue downstream over
western Canada, which will cause a pre-existing upper low over
the Upper Great Lakes to drop southeastward toward the Mid-
Atlantic and amplify into a shorter wavelength open wave. As
this occurs, large scale forcing for ascent will increase across
the area Saturday night. Precipitation could start as early as
the evening in the Alleghenies, before spreading eastward during
the overnight hours. Most solutions favor precipitation falling
as all snow, although some brief mixing with rain could occur
along/east of I-95 depending on the ultimate track of the
system.

As the wave amplifies, most models show a jet steak developing
downstream, with an enhanced band of snowfall developing in the
equatorward entrance region of the jet streak. While there`s
still some uncertainty with respect to exactly where this winds
up, some of the 12z models have this enhanced band of snow
developing in place along the I-95 corridor Saturday night. This
could result in a relative minimum in snowfall totals between
the Blue Ridge and the Alleghenies, with higher totals along the
I-95 corridor (where the best synoptic forcing will be) and in
the Alleghenies (where there will be some additional upslope
snow as the system departs). There`s still plenty of time for
things to change, and confidence in the forecast details remains
low this far out.

Any snow to the east of the mountains should come to an end by
around mid-morning Sunday, but upslope snow showers may continue
on and off in the Alleghenies through the day Sunday into Sunday
night. Low pressure will deepen as it departs to the east during
the day Sunday as a very strong (1040+ hPa) area of high
pressure builds southward across the Midwest. Gusty northwest
winds will usher the coldest airmass of the season into the
area, with temperatures likely dropping through the 20s during
the daylight hours on Sunday. Temperatures will drop back into
the single digits and teens Sunday night as strong northwesterly
winds continue. Wind chills will likely drop back into the
single digits above/below zero across much of the area, with
double digits below zero possible across the highest elevations.

High pressure will build overhead for Monday and Tuesday,
leading to dry but cold conditions. Highs on Monday will
generally be in the upper 20s and lower 30s, with upper 30s/low
40s on Tuesday.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR conditions are expected for all terminals through at least
Thursday, if not longer. A few showers could briefly impact the
metro TAF sites (particularly Baltimore) through 21Z-00Z. The
main story will be the periods of gusty winds as a series of
clipper-type systems race from the north-central U.S. toward
the Eastern Seaboard. Southerly gusts up to 20 to 25 knots are
likely through the early evening before a cold front sweeps
across the region. Winds shift to west-northwesterly tonight
behind this boundary between 00Z-06Z.

Blustery winds are expected on Thursday as gusts push into the
25 to 30 knot range during the afternoon hours. These elevated
winds may last into portions of the evening before decreasing
overnight. Another clpper-type system tracks toward the area on
Friday. Some threat for light snow exists, but confidence is low
on coverage and impacts to the terminals.

VFR conditions are expected during the daylight hours on Saturday.
Sub-VFR conditions appear likely late Saturday night into
Sunday morning in association with snow and low ceilings. Winds
will be out of the west on Saturday, and then gusty out of the
northwest on Sunday.

&&

.MARINE...
Hazardous marine conditions are likely with Small Craft
Advisories in place across all waters through early Thursday
evening. Initially, winds over the marine waters will be out of
the south-southwest with gusts in the 20 to 30 knot range. A
cold front sweeps through the waters later this evening with
winds shifting to west-northwesterly overnight.

A gusty pattern continues into much of Thursday which supports
the ongoing Small Craft Advisories. These may need to be
extended into Thursday night for portions of the waters.
Gradients weaken into Friday as high pressure briefly builds in;
gusts of 10 to 15 knots should be the highest observed.

Sub-SCA level westerly winds are expected during the day Saturday.
Winds will shift to out of the northwest and increase in strength on
Sunday behind an Arctic front. At least high-end Small Craft
Advisories appear likely on Sunday, and Gale conditions may be
possible.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Blizzard Warning until 10 AM EST Thursday for MDZ509.
     Winter Weather Advisory until 7 AM EST Thursday for MDZ510.
VA...Winter Weather Advisory until 7 AM EST Thursday for VAZ503.
WV...Blizzard Warning until 10 AM EST Thursday for WVZ501-505.
MARINE...Small Craft Advisory until 6 PM EST Thursday for ANZ530>543.

&&

$$

SYNOPSIS...BRO/DHOF
NEAR TERM...BRO/DHOF
SHORT TERM...BRO/DHOF
LONG TERM...KJP
AVIATION...BRO/DHOF/KJP
MARINE...BRO/DHOF/KJP